Lotus Europa Community
Lotus Europa Forums => Garage => Topic started by: S2Zetec54 on Wednesday,April 21, 2021, 01:36:35 PM
-
Hi All
Car slightly pulling when braking so checked the vehicle and found the hub on the outboard shaft, near side in a UK right hand drive car...ie the left looking from the rear, loose...further investigation revealed a rounded off D washer (sorry don't know the proper name)
Anyway, using loctite 660 (635 too expensive) to lock/fill the splines properly and then torque it up properly. We'll see how it works and if that doesn’t I'll have another go with 635 etc....Good learning experience to be honest
My question, and I have searched, is can one buy left hand threaded outboard shafts to stop this propensity to undo?
Would this be the answer? Prob very expensive even with a group buy
-
I’ve never heard of one but there are alternate ways of locking that nut. My machinist drilled an axial hole at the threads of the nut and the outboard shaft, tapped it and screwed and loctited a set screw or grub screw in it. It seems I’ve heard of other locking methods but I’m drawing a blank at the moment.
-
In 50 years of Europa ownership I've never had the nut loosen, but others obviously have. Usually the outboard shaft bearing journal pounds out and play develops there. Lotus should have used hardened steel and the journal needed to cover all of the bearing width, not half. At least they could have improved the original Imp design. Failures occur on the RR also so I'm not sure the thread direction is much of a factor. Best redesign seems to be the solid hub and shaft with the u joint bolted inboard of the housing.
-
D washer = lock tab washer
The most common way they loosen is the collapse of the mild-steel, inner spacer. Another is when they weren't tightened properly. You can't just tighten the nut. You need to tighten the nut, drive and corner it hard, tighten the nut, driven corner it hard, and keep repeating until it's stable. Then bend the lock-tabs.
This is why you use 635. It is a slow setting compound and gives you time to assemble and go through the tightening process before it sets.
-
In answer to your question about the axles, I believe the answer is yes. Here's the link
http://www.pamotorsport.com/for_sale/index.php?option=com_virtuemart&view=productdetails&virtuemart_product_id=279&virtuemart_category_id=36&Itemid=109
If you haven't yet read the analysis by Richard H on this problem, then do read it before you do anything else about this
https://groups.io/g/LotusEuropa/files/Stress%20analysis%20of%20Europa%20rear%20axle.pdf
-
Thank you everyone those are incredibly useful answers and links.
BDA, the drilling through and or use of a castlegated is a useful idea and I will keep up my sleeve. As you have done I would leave in the hands of a machinist if I go down this route
JB thank you. I had read previous posts by you on this and I am embarrassed to say I am trying 660 first despite your sensible advice about 635 and the proper tightening technique before finally deploying the lock tab washer. She's loosened before on the RLeft but this is the first time that any sort of glue has been used....so there maybe damage that will mean my efforts are in vain anyway. If she fails again I will use new parts and your technique along with 635
Gideon that is a great link...I am excited to call them to discover the price. I will post a price once I have. I am afraid your link to RichardH's analysis does seem to let me see anything....I'll do a RH search on this forum and see if anything comes up.
Thank you all. I'll let you know how my current attempt has gone.
-
I reckon that Richard's analysis is the most important thing for you to read. You should join the groups.io mailing list to get access to the files stored there anyway. It was too big to include as a single file here, but I was able to split it into separate pages. Maybe that'll work.
-
If you haven't yet read the analysis by Richard H on this problem, then do read it before you do anything else about this
https://groups.io/g/LotusEuropa/files/Stress%20analysis%20of%20Europa%20rear%20axle.pdf
I have seen that analysis before but never took the time to read it but your suggestion prodded me to finally read it. Very interesting. While I certainly don’t dispute his analysis, I have always understood that changes in the TC/TCS improved the situation (rather than make it worse). I certainly haven’t done a study on TC stub axle or bearing failure like the author did so I could be ignorant of the situation but I have heard of very few failures on TCS. Maybe somebody can update me.
Our own andy harwood started investigating using VW stub axles and CV joints. The stub axles are hardened and there is large assortment of axle lengths. It seems like a very good “final” solution that doesn’t seem to require a whole lot of development.
-
Thanks for the PA Motorsports Europa axle page. Look very interesting in that they're better steel and outer bearing journal is as wide as the bearing because they shortened the spline section.
Wonder if the inner journal is 30mm? Wrote off to get more info.
-
Hi All just had a very nice conversation with Peter at PA Motorsport. He uses these for his single seaters. He knows they fit series 1 Europas but is unsure of later versions. I think he said they were Imp outboard driveshaft. So do the series 1's fit series 2's.? They are 295 for each one and 24 for each nut....didn't ask if that was plus vat taxes etc...that's £
I said i would send him any engineering drawings I could get my hands on to show the series 2 dimensions etc...i'll go digging when I get home unless someone has a pdf of these dimensions we could rely on.
-
S1 and S2 axles are the same.
-
S1 and S2 take the same rear stub-axle.
That PA axle looks to be the perfect, bolt-on fix. Combined with hardened spacers and you should be good.
-
Thank you JB and Swifty thats excellent news. I have just read R Hills article kindly downloaded by Gideon, terrific article which is fascinating and really useful...well worth a read thanks to Gideon.
Hopefully what I have just done will buy me a little time while I accumulate the parts and do both sides using all the recommendations plus the inner bearing recommendations in the Hill Analysis.
Cheers everyone
-
OK, forgot to mention another source of "hub nut loosening". That is a soft lock-tab washers. Most of the washer you can get are "soft" steel so you can fold it over. Well, soft works both ways and it can "thin" out under pressure "loosening" the hub. A proper lock tab washer will be hardened steel with a foldable tab spot welded to it.
-
Thanks JB...good point. I guess I have to go to a machinist/engineer and specify how I would like these components and their hardness ?.....I'll do a search and see if there's anything off the shelf on the web somewhere....we're quite lucky locally and have a few engineers around with good reputations
Cheers
-
I found the hub nut came loose on my S2, after very careful examination we came to the conclusion that the Imp stubshaft was made of a mild steel which stretched & they were made to a price of zero, my machinist mate made a stub shaft & nut in EN24 (4340 US), end of problem, torque the heck out of it, doesn't slacken with 150bhp, an LSD & hillclimb slicks.
-
I think this may of been an issue on my 550k mile europa. As one of the hub nuts on the rear. Looks like it has been altered to combat it.
-
I think this may of been an issue on my 550k mile europa. As one of the hub nuts on the rear. Looks like it has been altered to combat it.
550k?!?!?!
-
Yes. Lol
-
Ok update...
I am going to buy a set of these drive shafts from PA motorsports, apparently they are EN24 he's going to turn them Down to 30mm to help with bearing choice and I think i am going to get him to turn up some inner spacers for me which he uses for his formula series cars where, if I understand correctly the contact area is larger at the ends than in the middle
After all this though I am rethinking which side to fit the left hand thread.....with old knock on wheel you'd put the left hand thread on the right hand side of the car.....thats right isnt it?? SoI am slightly befuddled
.....or does the D washer play a part here?
-
Good question about the thread orientation. My GT40 has left hand threads on the right side knockoffs. Europa owners don't seem to have loosening problems with RH threads on R side axles.
Seems I've seen this discussion before.
-
For the purposes of this thread I have been provided with this drawing which shows the dimensions of what I am buying
I have also added a screenshot of the inner spacer dimensions for all our models as I am interested in the following link being applied to my car for increased inner bearing contact using the 30mm bearing and a bespoke spacer such as this....may not be appropriate but intriguing
http://pamotorsport.com/for_sale/index.php?option=com_virtuemart&view=productdetails&virtuemart_product_id=216&virtuemart_category_id=10&Itemid=109
Anyway...feel free to comment. (Not sure of the protocol of using grabbed information from the internet, I have permission from PA Motorsport but not the other one..would a moderator delete if necessary?)
-
Can somebody tell me if the diameter of the inside bearing land(?) (31 mm for S2 and 30 mm for TC) and the size of the U-joint the only dimensions that are different on those stub axles? Since they will turn the inside bearing land to 30 mm, do they also provide examples for the bigger TC U-joints?
These are supposed to be made of EN24 (which I think equates to 4340 steel in the US). This is very strong stuff (min yield = ~100,000 psi)! Depending on the heat treatment, I guess it could be much higher!
-
By heat treating EN24 it doesn't get harder like a lot of specialist steels which also becomes more brittle, it gets tougher which is more ideal for the applications we use it for, not many better steels above this, we have used some steel called M300 which is a lot tougher
-
Thanks for the clarification!
I finally took a look at your cars! Very interesting collection!
-
Does anyone have a dimensional comparison for the two sizes of u-joints (TC & Special vs S1 & S2). Is it just the diameter of the u-joint bearing caps that is larger, or are the u-joint assemblies longer end to end as well?
-
I have a load of u joints in my garage. I’ll have to get a picture and measure after work tomorrow.
-
The TC/S ujoint is substantially larger all round.
-
My PA rear stub axles have arrived.
By the way there are no flats on the threads so one can't use the traditional D folding tab washer. As they are handed I'll try them like this first relying on the thread to keep them tight
Anyway I will use Richard Winters spacers and rear hubs for the rebuild along with new bearings
-
Lovely! 8)
-
Great! They look beautiful!
I hope you’ll take some time and report on your impressions, how it all fits together, etc.
Can you give us an idea of the cost?
-
Thank you.
Ok 'burn after reading'.....that little lot cost me £652 which included £14 for post..i'll offer up the old hubs but it seems sensible to buy new if there's any doubt etc...
I will update this thread with the process i'm going to follow and my testing when it's installed
One thing I haven't asked Peter yet is if I should or could torque to a higher level
-
Very Nice! Are the axles and yokes machined from a single bar of steel?
-
I've been wondering, do you put the right-hand thread on the right side, or vice versa?
-
Thank you.
Ok 'burn after reading'.....that little lot cost me £652 which included £14 for post..i'll offer up the old hubs but it seems sensible to buy new if there's any doubt etc...
That seems like a pretty good price!
-
...are they made from a single piece or welded...good question....I assumed they were one piece...I left them at work...Can you weld EN24? ....seem to remember that one had to be very careful and it required welding with the en24 metal at very high temperatures......but I read it a long time ago not sure if I remember correctly anyway these things are used in his single seaters so I am pretty confident they'll be strong enough.
So my plan is right hand thread on left hand side and left hand thread on right hand side....That was the advice from Peter at PA
Anyway, should be fun trying this.....will assemble all the parts I need before I start....so far the last retightening using lock tight has actually worked rather well...ironically!
Serge Sleurs has a good episode about putting the hub together on you tube...so intend to have the manual to hand and watch Sleurs a few times before I start
-
Ok 'burn after reading'.....that little lot cost me £652 which included £14 for post..i'll offer up the old hubs but it seems sensible to buy new if there's any doubt etc...
Ok, that's slightly more than the OEM parts but personally I think that's quite reasonable for what's a custom built, low volume component. And it's likely to be "fit and forget" which is always worth a few quid to me.
It's very nice kit, bookmarked for "just in case". Thank for posting that up.
Brian
-
Just remembered I never sent the pics of the u joints
-
Here they are
-
I have a spare set of U-joints that should be for a TCS and the cup measures 27mm across so yours must be S1/S2 U-joints. That's not surprising since the stub axles started life as S2 stub axles.
Were you able to tell if they were welded or a single piece?
-
....well if it's welded I can't see the join...but then I wouldn't really know what I'm looking for
I'll post some super up close photos....keep forgetting to bring them home....